The present invention is in a process for the preparation of tert. alkyl-tert. aralkyl peroxides with the general formula I ##STR4## where R represents an alkyl radical with 1 to 4 C-atoms, R', R" and R'" represent the same or different alkyl radicals with 1 to 5 C-atoms and n is a number between 1 and 3. In the process of the invention an olefin with the general formula II ##STR5## is reacted with a tert. alkyl hydroperoxide with the general formula III ##STR6## where R, R', R" and R'" and n have the meaning indicated above.
Tert. alkyl-tert. aralkyl peroxides are capable of forming relatively stable radicals at relatively high temperatures and are, therefore, particularly suitable as initiators for cross-linking synthetic resins. Moreover, they have the advantage of not forming decomposition products with unesireable properties. Processes for their preparation have, therefore, been known for some time. In particular, processes are widely used in the case of which a tert. alkyl hydroperoxide is condensed with the corresponding carbinol. A disadvantage of this process is that the carbinols have to be first produced from the corresponding hydroperoxide by reduction and that the diols and triols are solid compounds which are difficult to use in controlled amounts.
It is also known, e.g. from DE-OS 20 16 108 to prepare tert. alkyl-tert. aralkyl peroxides by reacting olefins with the general formula II with hydroperoxides under acid catalysis. It is essential for this process to use a medium which is completely free from water. Consequently, an anhydrous hydroperoxide must be used and the acid must be in the water-free state. When hydrochloric acid is used, this means that gaseous hydrogen chloride must be employed. Practically anhydrous hydroperoxide is complicated and dangerous to prepare. In addition, this known process required long reaction times and yet results in low yields with a low purity product.
It was, therefore, an object of the present invention to develop a process for the preparation of tert. alkyl-tert. aralkyl peroxides in the case of which the use of gaseous hydrogen chloride and anhydrous hydroperoxide is not necessary and which can be carried out within a short reaction time with high yields.